Subject: bug#24730: rmdir/mkdir error(s) and/or not working "reciprocally" w/each other

From: Reuti <[email-masked]>
Date: Tue, 18 Oct 2016 22:50:57 +0200

Am 18.10.2016 um 22:33 schrieb Eric Blake:

> tag 24730 notabug
> thanks
> 
> On 10/18/2016 02:49 PM, L. A. Walsh wrote:
>> 
>> It doesn't seem rmdir and mkdir are behaving "reciprocally"...
>> 
>> If I type
>> 
>> mkdir -p ./a/b/c   # no error
> 
> . already exists, so mkdir silently does nothing,
> ./a needs to be created,
> ./a/b needs to be created,
> ./a/b/c needs to be created
> 
>> rmdir -p ./a/b/c   # get error msg, but a,b,c removed.
> 
> ./a/b/c needs to be removed,
> ./a/b needs to be removed,
> ./a needs to be removed,
> . needs to be removed, but you can't do that, hence the error
> 
> The apparent asymmetry is due to the POSIX rules on how '.' is treated;
> but we can't change the behavior of either of these commands, because
> they are both following the POSIX rules.
> 
> If you want symmetry, omit the leading './', as in:
> 
> $ mkdir -p a/b/c
> $ rmdir -p a/b/c
> 
>> 
>> 1) thinking either rmdir shouldn't generate an error or mkdir should
>> 
>> mkdir -p a/../b      # no error
> 
> a needs to be created,
> a/.. already exists, so it silently does nothing,
> a/../b needs to be created
> 
>> rmdir -p a/../b      # error, but a & b removed
> 
> a/../b needs to be removed,
> a/.. needs to be removed, but you can't do that,
> at this point, POSIX is fuzzy whether to attempt to remove 'a', or to
> give up since 'a/..' was already an error; but obviously coreutils
> removes 'a'

What version of core-utils shows this behavior. In the latest one it's not removed AFAICS.

- -- Reuti

> 
>> 
>> 2) similar comment to above -- leading to:
>> 
>> for rmdir, if "-p" is used, then as similar to "mkdir -p":
>>  (no error if existing, make parent directories as needed)
>> 
>> rmdir -p should be
>>  "no error if dir not empty, but directories are followed
>> and deleted as possible".
> 
> Sadly, while that might be a nicer definition for 'rmdir -p', it doesn't
> match the POSIX requirements nor the historical behavior, so we can't
> really change it now.
> 
> So I'm marking this as not a bug, as there is nothing to change.
> 
> -- 
> Eric Blake   eblake redhat com    +1-919-301-3266
> Libvirt virtualization library http://libvirt.org
>